895 resultados para Bit commitment


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Universidade Estadual de Campinas. Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas. Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Identidade é composta pelos valores, crenças e metas com que um indivíduo está comprometido. Existem quatro estados de identidade: difusão, pré-fechamento, moratória e identidade estabelecida, identificados de acordo com a presença de exploração das alternativas e com a intensidade dos compromissos. Este trabalho verificou os estados de identidade em que se encontravam 753 adolescentes de 15 a 18 anos, estudantes do Ensino Médio de escolas públicas de São Paulo que responderam ao EOMEIS 2, uma escala tipo Likert que avalia os estados de identidade. A maioria dos adolescentes encontrava-se em moratória. Verificou-se uma associação positiva entre o sexo feminino e os estados de moratória e identidade estabelecida; entre a primeira série do Ensino Médio e o estado de pré-fechamento.

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O objetivo deste ensaio é refletir acerca da relação entre o primado da forma em nossa sociedade, que se expressa também nos âmbitos políticos e educacionais, e a formação de indivíduos pouco diferençados, no que se refere à sua sensibilidade, percepção e pensamento; tem como hipótese que a ênfase na forma, em diversos domínios sociais, em detrimento do conteúdo específico ao qual deveria se vincular contribui com a formação de indivíduos que têm dificuldades de se identificarem entre si e, por isso, de se desenvolver, sendo propensos à frieza, a uma ausência de percepção das contradições e conflitos sociais e a um pensamento basicamente adaptativo. Essa reflexão é desenvolvida tendo como referência obras de pensadores que constituíram a denominada Escola de Frankfurt, tais como T. W. Adorno, M. Horkheimer e H. Marcuse, e a Psicanálise Freudiana.

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A anemia por deficiência de ferro configura um problema epidemiológico da maior relevância atuando nos gastos públicos de saúde, nas consequências sociais do aumento de riscos no período gestacional, na redução da produtividade e, ainda, nas consequências, em longo prazo, do desenvolvimento mental. Algumas datas marcam o envolvimento do governo brasileiro em busca de alternativas de controle da deficiência marcial: 1977 - 1ª Reunião do Ministério da Saúde (INAN), com especialistas nacionais e internacionais, para discutir perspectivas e intervenções para o controle da anemia; 1982/83 - distribuição de suplemento de ferro para a clientela do Programa de Atenção à Gestante e dosagem de hemoglobina na 1ª consulta; 1992 - assinatura de compromisso brasileiro de reduzir em 1/3 a prevalência de anemia em gestantes; 1994 - implantação do Programa de Leite Vivaleite, no estado de São Paulo, fornecendo leite fortificado com ferro a famílias com crianças até 6 anos e renda inferior a dois salários mínimos; 2002/junho 2004 - fortificação das farinhas de trigo e de milho com ferro; 2005 - programa de suplementação de ferro a lactentes; 2009/março - divulgação do resultado do levantamento de prevalência de anemia em mulheres (15-49 anos) e crianças (6 - 59 meses) no Brasil; 2009/agosto - foi reeditada a Portaria no 1793/GM/agosto/2009 do Ministério da Saúde, instituindo a Comissão Interinstitucional para implementação, acompanhamento e monitorização das ações de fortificação das farinhas de trigo e milho e seus subprodutos.

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The relationship between companies is an important issue in the management of supply chains. Several aspects relating to the flow and exchange of information along the chain are considered as having a decisive influence on the success of this relationship. The main objective of this work was to structured and test models that link aspects of this nature with performance and the purchaser-supplier relationship in the supply chain. Aspects relevant to communication and the use do IT in relationships between companies were investigated. The importance of performance in this relationship was also investigated. The research were based on empirical data obtained by means of structural equation modeling. The results show that some aspects contribute in a significant way to the success of this relationship while others that, a priori, are considered important make no contribution.

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The 60kDa heat shock protein family, Hsp60, constitutes an abundant and highly conserved class of molecules that are highly expressed in chronic-inflammatory and autoimmune processes. Experimental autoimmune uveitis [EAU] is a T cell mediated intraocular inflammatory disease that resembles human uveitis. Mycobacterial and homologous Hsp60 peptides induces uveitis in rats, however their participation in aggravating the disease is poorly known. We here evaluate the effects of the Mycobacterium leprae Hsp65 in the development/progression of EAU and the autoimmune response against the eye through the induction of the endogenous disequilibrium by enhancing the entropy of the immunobiological system with the addition of homologous Hsp. B10. RIII mice were immunized subcutaneously with interphotoreceptor retinoid-binding protein [IRBP], followed by intraperitoneally inoculation of M. leprae recombinant Hsp65 [rHsp65]. We evaluated the proliferative response, cytokine production and the percentage of CD4(+)IL-17(+), CD4(+)IFN-gamma(+) and CD4(+)Foxp3(+) cells ex vivo, by flow cytometry. Disease severity was determined by eye histological examination and serum levels of anti-IRBP and anti-Hsp60/65 measured by ELISA. EAU scores increased in the Hsp65 group and were associated with an expansion of CD4(+)IFN-gamma(+) and CD4(+)IL-17(+) T cells, corroborating with higher levels of IFN-gamma. Our data indicate that rHsp65 is one of the managers with a significant impact over the immune response during autoimmunity, skewing it to a pathogenic state, promoting both Th1 and Th17 commitment. It seems comprehensible that the specificity and primary function of Hsp60 molecules can be considered as a potential pathogenic factor acting as a whistleblower announcing chronic-inflammatory diseases progression.

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The authors present a comparative analysis between a triple-band S-C-L erbium-doped fibre amplifier and a commercial semiconductor optical amplifier in a CWDM application scenario. Both technologies were characterised for gain and noise figures from 1480 to 1610 nm (S, C and L bands) and their systemic performances were evaluated in terms of bit error rate measurements for a wide range of optical power levels.

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A secure communication system based on the error-feedback synchronization of the electronic model of the particle-in-a-box system is proposed. This circuit allows a robust and simple electronic emulation of the mechanical behavior of the collisions of a particle inside a box, exhibiting rich chaotic behavior. The required nonlinearity to emulate the box walls is implemented in a simple way when compared with other analog electronic chaotic circuits. A master/slave synchronization of two circuits exhibiting a rich chaotic behavior demonstrates the potentiality of this system to secure communication. In this system, binary data stream information modulates the bifurcation parameter of the particle-in-a-box electronic circuit in the transmitter. In the receiver circuit, this parameter is estimated using Pecora-Carroll synchronization and error-feedback synchronization. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. During the demodulation process, the error-feedback synchronization presented better performance compared with the Pecora-Carroll synchronization. The application of the particle-in-a-box electronic circuit in a secure communication system is demonstrated.

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A new cryptographic hash function Whirlwind is presented. We give the full specification and explain the design rationale. We show how the hash function can be implemented efficiently in software and give first performance numbers. A detailed analysis of the security against state-of-the-art cryptanalysis methods is also provided. In comparison to the algorithms submitted to the SHA-3 competition, Whirlwind takes recent developments in cryptanalysis into account by design. Even though software performance is not outstanding, it compares favourably with the 512-bit versions of SHA-3 candidates such as LANE or the original CubeHash proposal and is about on par with ECHO and MD6.

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For the last decade, elliptic curve cryptography has gained increasing interest in industry and in the academic community. This is especially due to the high level of security it provides with relatively small keys and to its ability to create very efficient and multifunctional cryptographic schemes by means of bilinear pairings. Pairings require pairing-friendly elliptic curves and among the possible choices, Barreto-Naehrig (BN) curves arguably constitute one of the most versatile families. In this paper, we further expand the potential of the BN curve family. We describe BN curves that are not only computationally very simple to generate, but also specially suitable for efficient implementation on a very broad range of scenarios. We also present implementation results of the optimal ate pairing using such a curve defined over a 254-bit prime field. (C) 2001 Elsevier Inc. All rights reserved.

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Since the 1990s several large companies have been publishing nonfinancial performance reports. Focusing initially on the physical environment, these reports evolved to consider social relations, as well as data on the firm`s economic performance. A few mining companies pioneered this trend, and in the last years some of them incorporated the three dimensions of sustainable development, publishing so-called sustainability reports. This article reviews 31 reports published between 2001 and 2006 by four major mining companies. A set of 62 assessment items organized in six categories (namely context and commitment, management, environmental, social and economic performance, and accessibility and assurance) were selected to guide the review. The items were derived from international literature and recommended best practices, including the Global Reporting Initiative G3 framework. A content analysis was performed using the report as a sampling unit, and using phrases, graphics, or tables containing certain information as data collection units. A basic rating scale (0 or 1) was used for noting the presence or absence of information and a final percentage score was obtained for each report. Results show that there is a clear evolution in report`s comprehensiveness and depth. Categories ""accessibility and assurance"" and ""economic performance"" featured the lowest scores and do not present a clear evolution trend in the period, whereas categories ""context and commitment"" and ""social performance"" presented the best results and regular improvement; the category ""environmental performance,"" despite it not reaching the biggest scores, also featured constant evolution. Description of data measurement techniques, besides more comprehensive third-party verification are the items most in need of improvement.

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In this work, a wide analysis of local search multiuser detection (LS-MUD) for direct sequence/code division multiple access (DS/CDMA) systems under multipath channels is carried out considering the performance-complexity trade-off. It is verified the robustness of the LS-MUD to variations in loading, E(b)/N(0), near-far effect, number of fingers of the Rake receiver and errors in the channel coefficients estimates. A compared analysis of the bit error rate (BER) and complexity trade-off is accomplished among LS, genetic algorithm (GA) and particle swarm optimization (PSO). Based on the deterministic behavior of the LS algorithm, it is also proposed simplifications over the cost function calculation, obtaining more efficient algorithms (simplified and combined LS-MUD versions) and creating new perspectives for the MUD implementation. The computational complexity is expressed in terms of the number of operations in order to converge. Our conclusion pointed out that the simplified LS (s-LS) method is always more efficient, independent of the system conditions, achieving a better performance with a lower complexity than the others heuristics detectors. Associated to this, the deterministic strategy and absence of input parameters made the s-LS algorithm the most appropriate for the MUD problem. (C) 2008 Elsevier GmbH. All rights reserved.